Wf object

The Wf class just includes the Waterfall module (and Flow is just its alias). It makes it easy to create standalone waterfalls mostly to chain actions or to chain services including Waterfall or returning a Wf object.

Basically chain statements are executed in the order they appear. But if ever the waterfall is dammed, they are skipped.

If a main waterfall chains another waterfall and the child waterfall is dammed, the main waterfall would be dammed.

The point is to be able to be able to chain an expected set of actions whenever everything works fine. And to be able to quickly stop and get the errors back whenever something wrong happens.